The present invention relates to a structure for anchoring a wire end, and particularly, to an improvement of an anchoring structure suitably applicable tot a drum for winding an inner wire of a push-pull control cable, a pull control cable, and the like, in which an anchored wire end does not easily slip out of a receiving recessed portion.
In a conventional wire-winding drum, for example, equipped in a wire-driving device of a window regulator, a structure shown in FIG. 7 is employed as a means for anchoring a wire end in order to enable an easy attachment and detachment when the device is assembled or disassembled.
In the present specification, as shown in FIG. 7, a wire end 34 means a combination of a cable or wire 34a and an anchor or nipple 34b fixed to an end of the wire 34a.
In the conventional structure shown in FIG. 7, the wire 34a extends in a radial direction of the nipple 34b. The wire 34a is generally formed of a metal strand of wires. The nipple 34 is generally formed of a metal strand of wires. The nipple 34 is generally made of a relatively thin cylinder-like metal and has a diameter far larger than the outer diameter of the wire 34a and a thickness slightly larger than the outer diameter of the wire 34a.
A wire-winding drum 33 is provided witht a projection which has a hollow space like a key-hole having a side view corresponding to that of the wire end 34. That is to say, the hollow space comprises an open groove 31 having substantially constant depth along its length for the wire portion 34a, and an open recessed portion 32 for the nipple 34b.
The recessed portion 32 generally has a cylinder-like inner peripheral surface for receiving the nipple 34b without excess gap and has a depth deeper than that of the groove 31. The openings of the recessed portion 32 and the groove 31 are situated at the same side and are communicated with each other.
It the above-mentioned anchoring structure, the wire end 34 can be attached to the drum 33 by a parallel motion toward the drum, i.e. in the direction of arrow C, and can be detached from the drum by moving in the reverse direction.
However, the conventional structure has a drawback that the wire end 34 easily slips out of the groove 31 and the recessed portion 32 during the pushpull operation or pull-release operation of the wire 34a.
Now, it is to be understood that, though an inner wire of pull-control cable is not adapted to sufficiently receive a compression force, the wire can actually transmit an axial compression force in some extent based on construction thereof. That is to say, though a long wire serves as a flexible cord and cannot support axial compression force, a short section of the wire can serve as a flexible or yieldable rod for a weak axial compression force.
Therefore, not only a push-pull control cable, but also a pull control cable has the above-mentioned drawback.
In order to eliminate the above-mentioned drawback, Japanese Unexamined Utility Model Publications Nos. 108813/1985, 94570/1985 and 94571/1985 proposed some improved constructions.
The publications Nos. 108813/1985 and 94571/1985 disclose constructions each comprising a recessed portion provided with inwardly projecting projections capable of engaging with a peripheral surface of a nipple. In those constructions, the nipple is also inserted into the recessed portion by a parallel motion. However, since front openings are narrowed in those construction, there are disadvantages that detaching (and also the attaching) cannot be easily performed.
The publication No. 94570/1985 discloses a construction which has an oval recessed portion covered with cover plates while remaining an opening. In the construction, a nipple can be easily attached and detached. However, since the opening is larger than the plan view of the nipple, there is a disadvantage that the construction cannot sufficiently prevent an escape of the nipple.
An object of the present invention is to eliminate the above-mentioned problems and to provide a structure for anchoring a wire end in which the wire end can be easily attached to a recessed portion in assembling and detached in disassembling, and further, the wire does not easily slip out of the recessed portion during use.